Correct Answer (Detailed Explanation is Below)
A.
Length
Detailed Explanation
Angstrom (Å) is a unit of length equal to
10⁻¹⁰ metre. It is commonly used to express very small distances such as atomic radii, bond lengths and wavelengths of electromagnetic radiation. One nanometre is equal to 10 angstroms. The unit is named after Swedish physicist
Anders Jonas Ångström.